This invention relates to an optical character reader for accurately reading characters or symbols printed on a sheet.
Generally, the optical character reader scans characters on a sheet, images the characters through a lens system on an image sensor comprising a photoelectric conversion element, converts analog signals from the image sensor into binary signals corresponding to the background region and the characters on the sheet, and discriminates the characters on the sheet by the use of a discrimination circuit. For reading the characters printed on the sheet such as slips or price tags, a hand-scan type optical character reader (to be hereinafter called the hand scan OCR) which hand-operates a scanning unit and a stationary type optical reader (to be hereinafter called the stationary OCR) which fixes the scanning unit and transports the sheet are used. These OCRs, as shown in FIG. 1, scans the objective characters 3 printed on a sheet 1, rightwardly or leftwardly in the direction of the arrow in the drawing to thereby carry out the reading operation.
When the characters 3 on the sheet 1 are read, however, a scanner 4 if often moved onto the character line from the base outside of the sheet 1 beyond the edge 2 of the sheet. Since the edges 2 at the sheet 1 are liable to be optically shaded, the shading often is read by mistake.